On 15 June 1944, the frigate HMS Blackwood (Lt.Cdr. Leslie Tillman Sly, RD, RNR) was on patrol as part of the 4th Escort Group in the west end of the English Channel to protect the ships of the Normandy landings, when she was hit by a Gnat from U-764 off Brittany. She foundered while under tow off Portland Bill the following day.
The wreck lies in 60 meters of water in position 50º07'00"N, 02º01'06"W.

25 Nov 1943German U-boat U-600 was sunk in the North Atlantic north-east of the Azores, in position 40°31'N, 22°07'W, by depth charges from the British frigates HMS Bazely (Lt.Cdr. J.V. Brock, RCNVR), and HMS Blackwood (Lt.Cdr. L.T. Sly, RD, RNR).